A soldering apparatus for soldering electronic components on a printed circuit board or a flux-applying device for applying flux on the printed circuit board is provided with rails for conveying the printed circuit board, which is adjustable to a width of the printed circuit board (see patent documents 1 and 2). A supporting member for supporting the conveying printed circuit board from below so that it is not flexible by its weight, in which a fixed position thereof to the screw shaft is changeable for a size of the printed circuit board, is known.
For example, in the soldering of the reflow device, the printed circuit board on which the solder paste has been previously printed is conveyed into the reflow device and heated therein. The solder paste contains powder solder and the flux. The flux is made by dissolving a solid component such as rosin, thixotropic agent and activator with solvent.
In the above-mentioned heating step, the flux evaporates and an interior of the reflow device is filled with it. More in detail, in a preliminary heating zone, the solvent in the flux components particularly evaporates to become flux fumes. The solid components such as rosin in the flux components also evaporate to become fumes and waft in the device when it is exposed to high temperature within a heating zone.
For example, when a part of the evaporated flux fumes is adhered to a surface of a member (screw shaft, nut or the like) for adjusting conveying rails for conveying the printed circuit board to be a width between the rails matching a size of the board and to a surface of a member (screw shaft, nut or the like) for adjusting the fixed position to support the board, it becomes liquid flux fumes with flowability accompanied by reduced temperature. The liquid flux fumes are soon solidified. Since the solidified flux fumes are hard to be removed and are strongly adhered, it is not easily possible to remove them by revolving the screw shaft. Accordingly, a movement of the nut is difficult so that it is very difficult to adjust the fixed position thereof to the screw shaft.
Further, in a jet soldering apparatus which jets molten solder to perform the soldering, there is a case where the solder scattered by the scatter of the molten solder is adhered hard into a ball to the member (screw shaft, nut or the like) for adjusting conveying rails for conveying the printed circuit board to be a width between the rails matching a size of the board. In this case, like the above-mentioned case, it is not also easily possible to remove them by revolving the screw shaft. Accordingly, a movement of the nut is difficult so that it is very difficult to adjust the fixed position thereof to the screw shaft.
In the flux-applying device, dripped flux is also adhered to the screw shaft and solidified so that the fixed flux is hard to be easily stripped by the revolution of the screw shaft. Accordingly, any similar problems occur such that the fixed position of the nut to the screw shaft cannot be changed by its movements.
On the other hand, any screw or nut, a part of a screw thread of which is cut by a predetermined length, has been disclosed as the nut having a function of removing the film adhered to the screw or nut (see Patent Documents 3 through 5).